Swimming fin device



Aug. 30, 1960 G. B. wooDs 2,950,487

SWIMMING FIN DEVICE: I

Filed Aug. 9, 1954 A "mmm,

l Fig. 2 ,g 30

' 'Zzl knuff/1110i United States intent SWIMMING FIN DEVICE George Bryant Woods, deceased, late of Washington, D C., by Doris McKay Woods, executrix, Washington, 11C., assignor of one-third to Edward F. Connors, Jr., Washington, D.C.

Filed Aug. 9, 1954, Ser. No. 448,514

13 Ciaims. (Cl. 9--304) This invention appertains to improvements in swimming appliances for use in rendering swimming easier and increasing the rate of movement of a swimmer in the water.

With increased interest in swimming, there is a present need for mechanical means not only to make swimming less taxing and etortless but also to enable the art of swimming to be taught easier and more eiectively to beginners. Further, with the new interest in underwater swimming, especially spear shing, there is a need for mechanical swimming appliances that will increase the rate of movement of a swimmer both on and under the water.

There are many types of known swimmers appliances, but none of such known constructions provides a potential propulsive force for forward thrust on each stroke of the leg. None of the known swimming devices is designed for two-way strokes of approximately equal propulsion force. While some of the devices included paddles or the like which were hingedly or pivotally attached to the feet of a swimmer, such paddles provided a propulsion action on only one stroke of the ieg and were hinged or pivoted for the sole reason to lessen the water resistance on the return stroke in preparation for the next propulsion stroke. Further, such prior devices were cumbersome and were tiring in use due to two factors viz. (l) inability to use such devices while executing proper leg strokes and necessity to alter proper leg movements to bring such devices into play as propulsion factors and (2) positioning of center of pressure in such devices out forward of the ball of the foot and, in most instances, out beyond the toes.

Cf late, rubber swim-tins have been designed and such devices generally include foot receiving portions and tin sections that project forwardly of such portions and eX- tend outwardly beyond the toes. Such fins, while comfortable, due to their lightness, are not entirely eiective since they have a limited working area, such working area is mainly beyond the toes of the foot and such devices lack a two-stroke or two-cycle thrust action, since only on one stroke of the leg can any propulsion force be obtained, the return stroke of the leg nding such tins merely treading water in their return to the start of the propulsion stroke.

it is, therefore, the primary aim and purpose of this invention to provide a swimming iin that will give a forward thrust on each stroke of the leg, such lin posessing a two-cycle or two-stroke action so that on each stroke of the leg, a forward thrust of equal magnitude is produced by the ns.

Another object of this invention is to provide a swimming fin which is pivotally mounted on the foot of a swimmer in such a way that the center of pressure of to the fline of swimming progress and which has a reciprocating two-cycle action to produce equal forward thrust from each of the two-way strokes of the legs in executing such strokes as the Hutter.

A further object of this invention is to provide a streamlined, lightweight and sturdy tin structure which can be comfortably used in the water, without any extra physical effort and which can be worn while walking on land and on the bottom of the water without impeding or interfering with natural walking motion.

The foregoing and ancillary objects, including economy of production and ease of use plus interchangeability of the ns from one foot to the other, are obtained by this invention, the best known form of which is described in the following description and illustrated in the accompanying drawings, wherein;

Fig. l is a side elevational view of the swimming n device showing it attached to the foot;

Fig. 2 is a vertical cross-sectional view taken on line 2 2 of Fig. @1;

Fig. 3 is a top plan view thereof with a fence forming water path shown formed on the n and Fig. 4 'is a side elevational view of Fig. 3.

Referring now more particularly to the drawing, the numeral iti generally designates the swimming iin of the present invention with the iin being adapted to be attached to each foot of the user.

With the designing of the tins i0, an effective fish-tail action has been accomplished. In other words, an effecV- tive two-way reciprocating fish-tail action has been accomplished. The action of the sh-tail propulsion principle, which is seen in nature in sailsh, swordsh and other fish, enables the swimmer to achieve a greater rate of movement than is possible with the naked feet.

The ins 10 are positioned to extend laterally from both sides or one side of the foot and may be disposed in a plane coincident with the bottom of .the foot or in parallel planes to the bottom of the foot at points vertically thereabove. The tins are pivoted to the foot for pivotal movement about the axis a-a, which is contained in a plane that transversely intersects the ball of the foot.

The line x-x represents the center of water pressure of the tins, such center of pressure being across the ball of the foot and disposed adjacent to and just forwardly of the axis a-a.

The tins have upper and lower working surfaces 14 and 16 which provides a two-cycle reciprocating motion of the fins about the axis a-a, such axis being particularly disposed relative to the foot to place the working surfaces at the correct angie of attack for each stroke of the alternating reciprocating motion of the legs. The center of resistance for both strokes is maintained at the point x-x and is disposed approximately at the ball of the foot. The tins are balanced due to the fact that the center of pressure is just slightly forward of the aXis .fr-a and thereby, lost motion is reduced to a minimum since very little of each reciprocating stroke of the fins is wasted while the iin is swung by Water pressure to its normal position as shown in Figure 6, wherein the two positions of the iin under the up and down stroke of the legs is shown. The tins, due to the pivotal asis in relation to the ball of the foot and the center of pressure in relation to the ball of the foot and its closeness to such axis, are designed to be driven through the water in a course at the best angle of attack to the line of swimming progress. It is to be particularly appreciated that the pivotal movement of the lins is not an idling swivelling action for the purpose of lessening the water resistance on the return stroke in preparation for the next propulsion stroke as is true in prior art constructions. Conversely, the pivotal mounting of the iins is for the specific purpose of obtaining the reciprocating,

two-cycle action of the tins in achieving an effective twoway reciprocating fish-tail action.

The tins are pivoted to a foot receiving means, one form of which is shown for exemplary purposes in Figs. 1-4 andis indicated by the reference numeral 18. Such form of foot receiving means, as illustrated, is merely '.exemplary, since with the mounting of the fins at various vertically spaced points relative to the bottom of the foot, it is obvious that various changes in the foot receiving means would be dictated. Y Y The foot receiving means 18 includes a U-shaped member 20 which maybe formed from plastic or alurnirium light weight, inexpensive and sturdy material. The U-shaped member 20 includes a support for the fin 10, shown in Figs. 1 and 2 and serves as the means for VVpivotally supporting the fm. The member 20 includes -a at web portion 22, which is positioned beneath the bottom of the foot 24 and is flat. The web portion 22 Ypreferably extends from a position just forward of the falanges of the toes and terminates rearwardly at a point I just rearward of the arch of the foot. Obviously, such axial length of the web portion 22 is primarily for comv`fort, when the user is walking on land or wading on the bottom of a water body with the swimming device attached. However, there is an additional factor which dictates the axial lengthY of the web portion 22 and such factor is the comfortable use of theV device while swimming. In this respect, the propulsive thrust force of the iinV will have no effect onrthe muscles of the foot .due to the Vfirm support afforded by the web portion 22. Also such portion strengthens the bottom of the foot and affords a firm protective surface therefor, when such portion of the foot is itself eifecting a propulsion -force,.coincident with the return stroke of the leg.

lntegrally' formed with the opposing longitudinal side edges of the web portion and positioned intermediate the ends thereof are upstanding sides 24 and 26. Such sides are disposed alongside the ball of the foot and terminate in reduced upper ends 28 and 30. The n 10 is formed .on itsunderside or, speaking in terms of the iin in use, on the upper working surface 14 with apertured ears 32 and 34. Such ears are disposed parallel to the sides 24 and 26, the ear 32 lying alongside the upper end of the side 30 and being pivoted thereto by a suitable pivot .pin 36. VThe ear 34 is spaced laterally from the side ,28 and is pivoted thereto by a pivot pin 38. The spacing of the ear 34 from the side 28 is for the purpose of providing a space for the spring 40 which is coiled on the shank of the pin 38 intermediate-the ear 34 and the side 28. The spring 40 has one end suitably anchored to the ear 34 and its opposite end suitably anchored. to the side 26 and functions solely to retain the tin in a plane parallel to the web 22 or, otherwise stated, to the bottom of the foot 24 when the wearer is walking. In other words,fthe purpose of the spring is to prevent the iin from dropping downward at its extending end Yand interfering with the normal walking movement of 'the foot. For this reason, it may be desirable to have the sides 24 and 26, whose sole function is to space the iin 10 vertically above the foot, position the fin a few inches above the ground so as not to interfere with the normal walking motion. lWith respect to the rested position of the iin, which is illustrated in Figs. l and 2, and for'which'purpose the spring 40 is provided, it is to be lnoted that the sides 24 and 26 terminate at their upper free ends in squared terminal points so that the working surface 14 can rest flatly in a horizontal plane on the sides, the iin being retained thereon by the spring 40.

An elastic or otherwise deformable foot encircling band 42 hasY its ends suitably attached by fasteners 44 to the junctureY point 'of the side edges of the web and the sides r24 and 26. Such band, as shown in Figs. 1 and 2, is formed so that the foot can be placed on the top of the web22 and moved forward into the open end of fthe band which will snugly tit Vover the instep. A heel 4of the Yside sections.

`of the tins. .foot is particularly designed to place the iin at the co1'- encircling strap 46 is suitably'atta'ched to the band 42 as by passing it through slots 48 in the band. The strap is adjustable in length and provided with a buckle or other suitable fastener means so that it can be adjustably tted to the heel. It is to be particularly noted from a consideration of Figure 1, that the pivots 36 and 38 are disposed forwardly of therear edges of the sides and that the pivots pivotally mount the iin 10 so that the tin pivots about an axis which is contained in a plane that transversely intersects the ball of the foot. It is to be also noted that the major` portion of the n is disposed forwardly of such axis and that, therefore, the center of water pressure is Yalong the line x-xY or immediately forward of the pivot or axis; Y

The tin 10, as shown in the drawings, includes two side sections 50 and 52, which are formed integrally with a connecting center section 54. The center section 54 is considerably reduced in width from the side sections and has concave rear and forward edges. The purpose ofV providing the relatively narrow center section 54 and having the forwardY and vrear edges thereof concave is and separately mounted, though they would have a common pivotal action and propulsion force. The side sections 5,0 and 52 are designed in a streamlined fashion so that they have a swept-back, trans-sonic appearance. Each of the sections tapers towards its outeredge and the outer edge and forward and rearward edges of the sections are tapered to a tine point to carry out the streamlined design. The rear edges 56 of the side sections extend forward and outwardly from the sides of the foot, as do the front edges 58, such rear edges being longer than the front edges.` The rear edges form an obtuse angle with the foot while the front edges form an acute angle therewith.

As an additional factor in the thrust force of the working surfaces 14 and 16 of the n, fences 60 on each of the side sections has been provided. The fences 60 are disposed perpendicular to the working surfaces and are disposed in laterally spaced, parallel relation on each The fences are disposed parallel to the axis of the foot or normal to the pivotal axis of the fin. The pair of fences on the working surface on each of the side sections will space apart laterally and cooperate to form a passageway 62 for the water. In other words, the fences channel the'water by forming the passageways 62 and the water is concentrated in the passageways and prevented from running laterally oif the -ns thereby reducing the effective force of the water.

It isl to be particularly noted that the fins are interchangeable from one foot to the other and that, through Vthe strap and elastic adjustments, the swimming devices 'the wrist.

It lis important that the hinge axis t4-a be located adjacent the center of water pressure in order to obtain complete forward thrust and it has been found that, relative ,location of the center of pressure and the hinge axis and lthe location ofA the'latter with respect to the ball of the foot are of importance in preventing twisting or fluttering The positioning of the axis in relation to the .5 'rect angle of attack, so that each of the working surfaces is positioned at the correct angle of attack for each stroke of the two-cycle, reciprocating motion. The locating of the center of pressure immediately forward of the axis a-a enables the tins to be balanced so that very little of each reciprocating stroke is wasted while the n is swung by water pressure to its new position, that is while the tin is moved about its axis to change from one working surface to the other working surface.

While the preferred form of this invention has been described in the foregoing and illustrated in the accompanying drawings, such description and illustration are merely exemplary in nature and, since other structural forms of the invention may be realized, the scope of the invention is only limited by the appended claims.

What is claimed tis:

l. A swimming device for attachment to a foot comprising a foot receiving means, a n pivotally carried by said means and means pivotally mounting the n to said foot receiving means for pivotal movement about an axis contained in a plane transversely intersecting the ball of a foot said fin having a center of water pressure disposed rearwardly of the toe portion of the foot and slightly forwardly of and immediately adjacent to the pivotal mounting means.

2. A swimming device for attachement to a foot comprising a foot receiving means, a tin having upper and lower working surfaces and means pivotally mounting the iin to said foot receiving means for pivotal movement in a curvilinear path of movement about -an axis contained in a plane transversely intersecting the ball of a foot with the working surfaces alternately providing a thrust propulsion as the leg is moved upwardly and downwardly said fin having a center of water pressure disposed rearwardly of the toe portion of the foot and slightly forwardly of and ,immediately adjacent to the pivotal mounting means.

3. A swimming device for attachment to a foot comprising a foot receiving means, a n having upper and lower working surfaces, and means mounting the n t said foot receiving means so that the working surfaces lie in the rest position of the n parallel to the bottom of the foot, said mounting means including a pivot mounting the iin for pivotal movement about an axis contained in a plane transversely intersecting the ball of a foot said fin having a center of water pressure disposed rearwardly of the toe portion of the foot and slightly forwardly of and immediately adjacent to the pivotal mounting means.

4. A swimming device for attachment to a foot comprising a foot receiving means, a fin having upper and lower working surfaces, and means mounting the n to said foot receiving means so that the working surfaces lie in the rest position of the tin parallel to the bottom of the foot, said mounting means lincluding a pivot mounting the n for pivotal movement about an axis contained in a plane transversely intersecting the ball of a foot, with the major portion of said iin being disposed forwardly of the pivot said iin having a center of water pressure disposed rearwardly of the toe portion of the foot and slighly forwardly of and immediately adjacent to the pivotal mounting means.

5. A swimming device for attachment to a foot comprising a foot receiving means, a n having upper and lower working surfaces, and means mounting the iin to said foot receiving means so that the working surface lie in the rest position of the n parallel to the bottom of the foot, said mounting means including a pivot mounting the iin for pivotal movement about an axis contained in a plane transversely intersecting the ball of a foot, said iin tapering from said pivot laterally of the foot said fin having a center of water pressure disposed rearwardly of the toe portion of the foot and siightly forwardly of and immediately adjacent to the pivotal mounting means.

6. A swimming device for attachment to a foot comprising a foot receiving means, a n having upper and lower working' surfaces, and means mounting the fin to said foot receiving means so that the working surfaces lie in the rest position of the n parallel tothe bottom of the foot, said mounting means including upstanding fixed supports on the foot receiving means and disposed on opposite sides of the foot at the ball thereof, a pivot mounting the fin to the supports for pivotal movement about an axis contained in a plane transversely intersecting the ball of a foot and disposing the iin above the instep of the foot, said fin being extended laterally from each side of the foot and having the major portion thereof disposed forwardly of the pivot said tin having a center of water pressure disposed rearwardly of the toe portion of the foot and slightly forwardly of and immediately adjacent to the pivotal mounting means and having a cut-out portion forwardly of the pivot to pass over the toes of the foot.

7. A swimming device for attachment to a foot comprising a foot receiving means, a n having upper and lower working surfaces, and means mounting the fin to said foot receiving means so that the working surfaces lie in the rest position of the fin parallel to the bottom of the foot, said mounting means including upstanding fixed supports on the foot receiving means and disposed on opposite sides of the foot at the ball thereof, a pivot mounting the fin to the supports for pivotal movement about an axis contained in a plane transversely intersecting the ball of a foot and disposing the fin above the instep of the foot, with the major portion of said fin being disposed forwardly of the pivot said fin having a center of water pressure disposed rearwardly of the toe portion of the foot and slightly forwardly of and immediately adjacent to the pivotal mounting means, and spring means operatively connected between the foot receiving means and the n to retain the fin in its rest position when the foot is placed at on the ground.

8. A swimming device for attachment to a foot comprising a foot receiving means, a fin having upper and lower working surfaces, and means mounting the fin t0 said foot receiving means so that the working surfaces lie in the rest position of the tin parallel to the bottom of the foot, said mounting means including upstanding fixed supports on the foot receiving means and disposed on opposite sides of the foot at the ball thereof, a pivot mounting the iin to the supports for pivotal movement about an axis contained in a plane transversely intersecting the ball of a foot and disposing the in above the instep of the foot, said Working surfaces having perpendicular, laterally spaced, parallel flanges, axially extending normal to the axis of movement and paralleling the direction of movement to form water confining pathways said iin having a center of water pressure disposed rearwardly of the -toe portion of the foot and slightly forwardly of and immediately adjacent to the pivotal mounting means.

9. A swimming device for attachment to a foot comprising a flat sole piece on which a foot is supported, a strap carried by the sole piece and adapted to fit over the instep of a foot to secure the sole piece to the bottom of a foot, supporting members upstanding from the sides of the sole piece and disposed in spaced, confronting relation, perpendicular to the ball of a foot and terminating above the instep of the foot, a n having wings connected by a thin bridge piece, said bridge piece transversely overlying the instep of the foot and said Wings laterally extending from the foot, means pivotally mounting the iin to the supporting members for pivotal movement thereof about an axis contained in a plane which transversely intersects the ball of the foot and said fin having the major portion of its wings extending forwardly of the pivotal mounting means and said lin having a center of water pressure disposed rearwardly of the toe portion of the foot and immediately forwardly of and adjacent to the pivotal mounting means.

10. A swimming device as claimed in claim 9, wherein the surfaces.

said bridge Ypiece has opbosing forward and rearward concave 'edges for accommodation by the foot of the pivotal movement ofthe iin. Y

11. vA swimming device Ias claimed in claim 9, wherein ua strap is carried by the supporting members and is jadapted to iit around the heel of the foot.

12. -A Swimming device as claimed in claim 9, wherein Vnormal to the axis of the tin andfchannel the Water on References Cited in the le of this patent UNITED STATES PATENTS Osterberg Oct. 13, 1914 Grundman V V A v Apr. 5,11921 lSnapp Ian. 28, 1930 Breeze Mar. 24, 1942 Messinger ..A Mar. 7, 1944 PATENTS Italy Aug. 23, 1949 www: 1-1...1 

